Topological semimetals and topological insulators in rare earth monopnictides [article]

Minggang Zeng, Chen Fang, Guoqing Chang, Yu-An Chen, Timothy Hsieh, Arun Bansil, Hsin Lin, Liang Fu
2015 arXiv   pre-print
We use first principles calculations to study the electronic properties of rock salt rare earth monopnictides LaX (X=N, P, As, Sb, Bi). A new type of topological band crossing termed 'linked nodal rings' is found in LaN when the small spin-orbital coupling (SOC) on nitrogen orbitals is neglected. Turning on SOC gaps the nodal rings at all but two points, which remain gapless due to C_4-symmetry and leads to a 3D Dirac semimetal. Interestingly, unlike LaN, compounds with other elements in the
more » ... ctogen group are found to be topological insulators (TIs), as a result of band reordering due to the increased lattice constant as well as the enhanced SOC on the pnictogen atom. These TI compounds exhibit multi-valley surface Dirac cones at three M̅-points on the (111)-surface.
arXiv:1504.03492v1 fatcat:u47mqgf2evdrveqoznydz4sohy